Playoff Odds Comparison: FanGraphs vs. A Sportsbook

With the recent addition of the ZiPS projections to the present site, the playoff odds that are also available within these electronic pages now feature both the ZiPS and Steamer figures as the raw material for those calculations.

“How do those playoff odds compare, for example, to what might be offered by a notable sportsbook?” a weblogger with an interest in producing content might wonder. “Yes, how do those FanGraphs playoff odds compare to what’s offered by a sportsbook?” a reader might wonder, as well, as part of his or her attempt to locate a distraction from whatever work ought to be done right now.

The answer to that question appears within the table below. Below that is a brief explanation on how that answer was produced, plus some notes on the consequences of the results. There’s a better than 50% chance, as well, that each column can be sorted by clicking on the relevant header.

Club Odds sWS% fWS% Diff
Rays 12.54 6.5% 3.4% 3.1%
Yankees 14.13 5.8% 2.9% 2.9%
Reds 21.21 3.8% 1.2% 2.6%
Orioles 36.00 2.3% 0.6% 1.7%
Phillies 41.39 2.0% 0.5% 1.5%
Royals 31.28 2.6% 1.2% 1.4%
White Sox 71.67 1.1% 0.1% 1.0%
Cubs 81.76 1.0% 0.0% 1.0%
Brewers 76.06 1.1% 0.5% 0.6%
Twins 127.18 0.6% 0.1% 0.5%
Mets 101.96 0.8% 0.3% 0.5%
Mariners 26.24 3.1% 2.7% 0.4%
Rockies 81.76 1.0% 0.6% 0.4%
Marlins 202.89 0.4% 0.1% 0.3%
D-backs 51.48 1.6% 1.3% 0.3%
Astros 505.70 0.2% 0.0% 0.2%
Padres 64.10 1.3% 1.3% 0.0%
Braves 19.16 4.2% 4.3% -0.1%
Rangers 16.98 4.8% 5.0% -0.2%
Blue Jays 35.78 2.3% 2.7% -0.4%
Pirates 31.28 2.6% 3.1% -0.5%
Giants 26.24 3.1% 3.8% -0.7%
Dodgers 8.08 10.1% 11.4% -1.3%
Nationals 13.12 6.2% 7.7% -1.5%
Indians 48.96 1.7% 3.3% -1.6%
Athletics 21.21 3.8% 5.5% -1.7%
Angels 21.21 3.8% 5.7% -1.9%
Cardinals 11.11 7.3% 9.3% -2.0%
Red Sox 11.61 7.0% 9.8% -2.8%
Tigers 10.10 8.1% 11.5% -3.4%

What I’ve done is convert the future lines currently available at Pinnacle Sports into World Series odds by finding the break-even point for each potential bet and then removing the vigorish. The results of this process are represented above under the column marked sWS% (for Sportsbook World Series percentage).

Also present in the table are the FanGraphs World Series odds (fWS%) produced by a combination both of the Steamer and ZiPS projections, plus the playing-time estimates provided by various of our authors. The column marked Diff represents the difference between the sportsbook and FanGraphs odds, where a positive figure suggests that the sportsbook prefers the club in question; a negative figure, that the club is favored by FanGraphs’ own projections.

Some notes on what’s present here:

  • For as conservative as the FanGraphs projections might appear, the odds implied by the Pinnacle lines are actually even more greatly so. The latter figures span a range of just 9.9%; the former, 11.5%. The standard deviation for Pinnacle’s implied playoff odds is 2.6%; for FanGraphs, it’s 3.5%.
  • The club most favored by Pinnacle is the Dodgers, at about 10% to win the World Series. The Dodgers are second, according to FanGraphs’ odds calculations, at slightly greater than 11%.
  • The club least favored by the sportsbook line presently is Houston, at basically 0%. This is also the case with the FanGraphs projections — with the Cubs also featuring basically a 0% chance of winning the Series.
  • The club most favored by the sportsbook line relative to FanGraphs is Tampa Bay — somewhat surprising, I suppose, though our forecasts are somewhat down on the Rays this year.
  • The club most favored by the FanGraphs odds, meanwhile, relative to the sportsbook line is Detroit.



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Carson Cistulli occasionally publishes spirited ejaculations at The New Enthusiast.


30 Responses to “Playoff Odds Comparison: FanGraphs vs. A Sportsbook”

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  1. Scout Cameron says:

    20 hot stove / business understanding. eesh.

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  2. Marco says:

    If you’re up for it, I’d love to see another one on the O/U on wins for the season.

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  3. Guy says:

    Note the top four are all AL East teams.

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  4. Well-Beered Englishman says:

    Wow. The Oakland A’s seem like a quality bet.

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  5. m_pemulis says:

    “a reader might wonder, as well, as part of his or her attempt to locate a distraction from whatever work ought to be done right now.”

    Who else got hit with that dagger of guilt?

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  6. Eric R says:

    If my math is right … and it probably isn’t :) … then $100 bets on the Indians, A’s, Angels, Cardinals, Red Sox and Tigers should pay out 45% of the time, rather than the 32% that Pinnacle projects.

    If the numbers are right then those six would give you you a weighted average of $732 at a cost of $600. If it wasn’t for the fact that the sportsbooks seem to be really really really good at this, I’d be tempted to throw a couple hundred dollars at it :)

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    • The Stranger says:

      I’m too lazy to do the math myself – did you factor in the vigorish?

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      • Eric R says:

        I didn’t, and I’m not too familiar with sports betting. On $600 worth of bets, about how much would the vigorish be? If my math is right, anything lower than 20% still puts those six teams as a net positive if Fangraphs odds end up pretty close to reality

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    • bobaloo says:

      If my understanding is right, sportsbook wants to balance dollar total on either side of a bet…crowd sourcing as it were

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      • novaether says:

        This is basically correct. Sports books want to balance bets and their odds so that they make money no matter what the outcome of the game. They use a vig to give themselves a margin of error. If you’re smarter than the masses, you can make money on sports betting. You need to be significantly smarter, though, to overcome the vig.

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        • Aaron (UK) says:

          This is basically incorrect. Modern sportsbooks seek to lay bad-value (for the bettor) bets. They tend to lose money when the public favourites win.

          Sportsbooks may try to distribute the vig more heavily onto the popular choices (e.g. NYY) but they are of course in competition with each other and it’s easier than ever for customers to compare odds between books.

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        • novaether says:

          The line-setting dynamic is certainly more complicated than I initially described, but the general point is correct. If a sportsbook has a large cash stash, they can afford to set their lines to implicitly bet against the public favorites. It’s a more dangerous strategy since they run the risk of running out of money on a bad streak, but it’s more profitable in the long run.

          To your own point, though, sportsbooks are all in competition with each other so you’re not going to see a sportsbook that is setting lines to deviate strongly from the basic strategy that bobaloo outlined above.

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        • Andrew says:

          This is correct. The sports books have no interest in being correct, they have every interest in producing a parity of investment on all sides to create a zero-sum game in terms of the gambling while profiting on the vigorish.

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        • Aaron (UK) says:

          Andrew, they have even more interest in making more money in the long term. The strategy you (and bobaloo/novaether) have described is suboptimal.

          Very small books (or one-man operations on exchanges such as on betfair) may aim to get a level-green book of say +2.5%. The larger sportsbooks would prefer to have e.g. a 50% chance of losing 15% and a 50% chance of winning 25%. This is what happens in practice.

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      • Aaron (UK) says:

        It’s precisely because they are in competition with each other that the book-balancing approach of shortening the crowd favourites doesn’t work – books that hold the price on the crowd favourite will end up taking more business.

        And if you cut the crowd favourite too far not only do you lose out on the square business to your rivals, but you will attract sharp business on the less-fancied team whose odds you’ve lengthened (business which will be -EV for you). Lose-lose.

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  7. NeverHit1stBase says:

    Carson is the guy that everyone gently makes fun of but has a major crush on, just throwing that out there.

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  8. JKB says:

    I think Fangraphs is underestimating the Rays Pitching this year by about 2 Wins. That may account for at least part of the variance with Pinnacle.

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  9. novaether says:

    ” [...] plus the playing-time estimates provided by various of our authors”

    Mr. Cistulli – are you referring to the FANS projections or have various fangraphs authors made and compiled their own playing time projections? I’d love to see them, if the latter is the case.

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    • jruby says:

      I believe the playing time estimates on the depth chart pages are what he’s referring to. These have indeed been assembled by FG authors

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  10. jwise224 says:

    I’m not a gambler, so I could be off here, but aren’t the odds produced by casinos and betting services devised to induce the most bets, rather than create the most accurate projection? They’re goal is make money whereas Carson’s goal is to use the most number of words possible when only one will do.

    For the record, I like Carson’s aims much more.

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  11. BDF says:

    Would like to see this exercise performed retroactively for out-of-nowhere WS teams like the 08 Rays, 69 Mets, or 67 Red Sox. Were they really bucking sabrmetric odds or just expectations odds?

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  12. Greg says:

    The vig wipes out any value arising from projection differences. For instance, I see the Tigers at +820 (break even at 12.2%).

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  13. Plucky says:

    I’d take Cardinals, Nats, and Pirates as my favorites against those odds. Pirates are a popular candiate for regression, but the idea they have a below-average chance at the WS seems silly. The NL’s middle class (talent-wise) is a lot smaller, I’d peg 6-7 teams as close to zero chance, whereas in the AL there are plausible cases for all but Astros/Twins/WhiteSox sneaking into the WC if things break right.

    Cards & Nats ought to win their divisions, and if the Cards don’t I’d think the Pirates have a way better shot then the Reds to be the upsetter. Cards + Nats + Pirates is 16.1%, I’d think 20-22% (50/50 WS, 50/50 vs LAD, token possibilities of ATL, SF, CIN) for the combination is a lot closer to fair

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    • Plucky says:

      Also, you could add LAD to that bet and have combined 26.2% chance that one of those teams wins. ‘The field’ ought to have way worse than 50/50 odds of beating LAD, STL, WAS, and PIT for the NL title and it’s pretty silly to put the WS as anythign but marginally different than 50/50

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  14. Aaron says:

    Using the additive percentage difference is really a screwed-up methodology. Not all percentage points are created alike in marginal value – for example, the Indians offer a theoretical EV% (expected value) of 1.94 (expected $0.94 profit per $1 wagered), while the “higher-ranked” Tigers offer a theoretical EV% of 1.42 (expected $0.42 profit/$).

    FWIW, I’m writing this comment from the sportsbook at which I set odds.

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